In order to determine whether decreased hemoglobin affinity for oxygen improves myocardial oxygenation in patients with stable angina, a double blind, randomized study will be performed whereby subjects with stable angina will undergo treadmill exercise prior to and after the intravenous administration of inosine-phosphate-pyruvate solution (IPP) or placebo solution. IPP increases 2,3 DPG and P50, the latter by about 5 torr.